By The Standards of The Solar System, Where are found the only comparable bodies of whose existence we have certain knowledge, the earth is not a large planet. For most of recorded history, on the other hand, it has certainly seemed so to its inhabitants, and only in recent decades has a different perception come to prevail, as instanced, for example, by the much-remarked Ward-Dubos book of 1972, Only One Earth — The Care and Maintenance of a Small Planet. In 1872 Phileas Fogg needed almost eighty days to go around the world, in 1961 Yuri Gagarin managed the feat in little more than eighty minutes, and nowadays less intrepid travellers than these think nothing of accomplishing the task using commercial aircraft in comfortably less than eighty hours. Photographic images and, in general, data of unlimited complexity meanwhile circle the globe virtually instantaneously. The technologies here are those of transport and communications but in most other areas of human activity too the twentieth century has seen similar technological strides.